
Well, my assumptions are as below:
1) [B][U]The weights of all the components are static.[/U][/B]
 In our products, all the components are static except the compressor(s), and the total vibration is less than 1mm (in fact, less than 100 micron), thus I believe that it can be ignored when calculating the pointloads if compared to few thousand KG static weights.
2) [B][U]There is no deflection at the supporting points of the unit base frame.[/U][/B]
 As the height level of the spring isolator can adjusted, we always instruct our client to adjust the spring isolators to the same height after the unit is sitting on it.
 Thus, I believe that we can assume no deflection at the supporting points of the unit base frame.
It may be that I did not tell these assumptions upfront, the discussion in here becomes complicated with the dynamic loads.
I will need some times to digest the formula posted by zeke. By the way, just looking at the final result of the example, ".22F,.24F,.26F,.28F", it seems like quite similar to my calculation in post #11. Is it?

No, and also your 4 support solution doesn't look right .
Since my solution used the same assumptions, it is also wrong.
I redid it for the 4 point and got
P1=.24F,P2=.191F
P3=.308F, P4=.260F
F=1500
CM located at 80,50